WASI P1 Libc + Browser Host for the D

[Kapendev]

With the recent release of [LDC 
1.43](https://forum.dlang.org/thread/vehouugxzztbccotijmg@forum.dlang.org) and its WASI add-on, I decided to spend some time with them and see how they work. The results are pretty nice!

Introducing: 
[wasip1libc-d](https://github.com/Kapendev/wasip1libc-d), the 
wasi-libc at home.
It's a basic libc and browser host that is mainly intended for my 
library called Parin.
Other D libraries work too, but I don't promise that everything 
works. At least with the default custom libc. There is an option 
to use the real wasi-libc with the browser host if needed.

Some of the D libraries I played with and worked are:

- inmath
- text-mode
- EMSI containers
- D-YAML
- dlib
- godot-math
- arsd (not everything)
- mir (probably also not everything)

You can test them yourself in the examples folder of the repo.
Before doing anything, make sure to download the WASI add-on. 
Projects that are not compatible with the `-betterC` flag need 
it. `-betterC` projects work without it.